I feel like there's a lot of fascists out there who deserve the title of most destructive school of thought way more. Religious fundamentalists, hate groups, etc.
Eh, let me give you an example. Bolivia was a very right wing country, but somehow they elected Morales. The reason why he got elected was that literally Hugo Banzer privatised the water of Bolivia to a consortium. That led all the rivers to be considered our of reach by the population and people got forbidden to collect rainwater and also were ordered to disconnect their houses from any private water source like water pits. That caused such an outrage that made Bolivia elect a left winger.
Plus the economic damage in some areas was comparable to what a war can cause, I live in the ABC region in Brazil that was once an industrial powerhouse and now people simply exist, there is are jobs anymore and the youth have no prospect of future. I see neoliberalism as the kind of stuff that can cause civilisation collapse without war. I dare to say that some less aggressive forms of communism like the Cuban one are less destructive than neoliberalism.